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Counting and characterising functions with “fast points” for differential attacks

Higher order derivatives have been introduced by Lai in a cryptographic context. A number of attacks such as differential cryptanalysis, the cube and the AIDA attack have been reformulated using higher order derivatives. Duan and Lai have introduced the notion of “fast points” of a polynomial functi...

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Main Authors: Ana Salagean, Matei Mandache-Salagean
Format: Default Article
Published: 2015
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Online Access:https://hdl.handle.net/2134/19814
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author Ana Salagean
Matei Mandache-Salagean
author_facet Ana Salagean
Matei Mandache-Salagean
author_sort Ana Salagean (1257498)
collection Figshare
description Higher order derivatives have been introduced by Lai in a cryptographic context. A number of attacks such as differential cryptanalysis, the cube and the AIDA attack have been reformulated using higher order derivatives. Duan and Lai have introduced the notion of “fast points” of a polynomial function f as being vectors a so that computing the derivative with respect to a decreases the total degree of f by more than one. This notion is motivated by the fact that most of the attacks become more efficient if they use fast points. Duan and Lai gave a characterisation of fast points and Duan et al. gave some results regarding the number of functions with fast points in some particular cases. We firstly give an alternative characterisation of fast points and secondly give an explicit formula for the number of functions with fast points for any given degree and number of variables, thus covering all the cases left open in Duan et al. Our main tool is an invertible linear change of coordinates which transforms the higher order derivative with respect to an arbitrary set of linearly independent vectors into the higher order derivative with respect to a set of vectors in the canonical basis. Finally we discuss the cryptographic significance of our results.
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spelling rr-article-94018702015-11-26T00:00:00Z Counting and characterising functions with “fast points” for differential attacks Ana Salagean (1257498) Matei Mandache-Salagean (7168481) Other information and computing sciences not elsewhere classified Higher order differential attacks Higher order derivative Cryptanalysis Polynomials over finite fields Information and Computing Sciences not elsewhere classified Higher order derivatives have been introduced by Lai in a cryptographic context. A number of attacks such as differential cryptanalysis, the cube and the AIDA attack have been reformulated using higher order derivatives. Duan and Lai have introduced the notion of “fast points” of a polynomial function f as being vectors a so that computing the derivative with respect to a decreases the total degree of f by more than one. This notion is motivated by the fact that most of the attacks become more efficient if they use fast points. Duan and Lai gave a characterisation of fast points and Duan et al. gave some results regarding the number of functions with fast points in some particular cases. We firstly give an alternative characterisation of fast points and secondly give an explicit formula for the number of functions with fast points for any given degree and number of variables, thus covering all the cases left open in Duan et al. Our main tool is an invertible linear change of coordinates which transforms the higher order derivative with respect to an arbitrary set of linearly independent vectors into the higher order derivative with respect to a set of vectors in the canonical basis. Finally we discuss the cryptographic significance of our results. 2015-11-26T00:00:00Z Text Journal contribution 2134/19814 https://figshare.com/articles/journal_contribution/Counting_and_characterising_functions_with_fast_points_for_differential_attacks/9401870 CC BY 4.0
spellingShingle Other information and computing sciences not elsewhere classified
Higher order differential attacks
Higher order derivative
Cryptanalysis
Polynomials over finite fields
Information and Computing Sciences not elsewhere classified
Ana Salagean
Matei Mandache-Salagean
Counting and characterising functions with “fast points” for differential attacks
title Counting and characterising functions with “fast points” for differential attacks
title_full Counting and characterising functions with “fast points” for differential attacks
title_fullStr Counting and characterising functions with “fast points” for differential attacks
title_full_unstemmed Counting and characterising functions with “fast points” for differential attacks
title_short Counting and characterising functions with “fast points” for differential attacks
title_sort counting and characterising functions with “fast points” for differential attacks
topic Other information and computing sciences not elsewhere classified
Higher order differential attacks
Higher order derivative
Cryptanalysis
Polynomials over finite fields
Information and Computing Sciences not elsewhere classified
url https://hdl.handle.net/2134/19814